The temporary names are derived systematically from the element's atomic number, and are only applicable for 101 ≤ Z ≤ 999.[1] Each digit is translated to a 'numerical root', according to the table. The roots are concatenated, and the name is completed with the ending suffix -ium. Some of the roots are Latin and others are Greek to avoid two digits starting with the same letter (for example, the Greek-derived pent is used instead of the Latin derived quint to avoid confusion with quad for 4). There are two elision rules designed to prevent odd-looking names.

If bi or tri is followed by the ending ium (i.e. the last digit is 2 or 3), the result is '-bium' or -'trium', not '-biium' or '-triium'.

If enn is followed by nil (i.e. the sequence -90- occurs), the result is '-ennil-', not '-ennnil-'.

The suffix -ium overrides traditional chemical suffix rules; thus elements 117 and 118 were ununseptium and ununoctium, not ununseptine and ununocton.[2] This does not apply to the final trivial names these elements receive once confirmed; thus element 117 and 118 are now tennessine and oganesson. For these trivial names, all elements receive the suffix -ium, except those in group 17 which receive -ine (like the halogens) and those in group 18 which receive -on (like the noble gases).

The systematic symbol is formed by taking the first letter of each root, converting the first to a capital. This results in three-letter symbols instead of the one- or two-letter symbols used for named elements.

As of 2016[update], all 118 discovered elements have received individual permanent names and symbols.[3] Systematic names and symbols are only used for the undiscovered elements beyond element 118, oganesson.

1.
Periodic table
–
The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configurations, and recurring chemical properties. This ordering shows periodic trends, such as elements with similar behaviour in the same column and it also shows four rectangular blocks with some approximately similar chemical properties. In general, within one row the elements are metals on the left, the rows of the table are called periods, the columns are called groups. Six groups have names as well as numbers, for example, group 17 elements are the halogens, and group 18, the noble gases. The periodic table can be used to derive relationships between the properties of the elements, and predict the properties of new elements yet to be discovered or synthesized, the periodic table provides a useful framework for analyzing chemical behaviour, and is widely used in chemistry and other sciences. The Russian chemist Dmitri Mendeleev published the first widely recognized periodic table in 1869 and he developed his table to illustrate periodic trends in the properties of the then-known elements. Mendeleev also predicted some properties of elements that would be expected to fill gaps in this table. Most of his predictions were proved correct when the elements in question were subsequently discovered, Mendeleevs periodic table has since been expanded and refined with the discovery or synthesis of further new elements and the development of new theoretical models to explain chemical behaviour. The first 94 elements exist naturally, although some are only in trace amounts and were synthesized in laboratories before being found in nature. Elements with atomic numbers from 95 to 118 have only been synthesized in laboratories or nuclear reactors, synthesis of elements having higher atomic numbers is being pursued. Numerous synthetic radionuclides of naturally occurring elements have also produced in laboratories. Each chemical element has an atomic number representing the number of protons in its nucleus. Most elements have differing numbers of neutrons among different atoms, with variants being referred to as isotopes. Isotopes are never separated in the table, they are always grouped together under a single element. Elements with no stable isotopes have the masses of their most stable isotopes. In the standard periodic table, the elements are listed in order of increasing atomic number, a new row is started when a new electron shell has its first electron. Columns are determined by the configuration of the atom, elements with the same number of electrons in a particular subshell fall into the same columns. Thus, it is easy to predict the chemical properties of an element if one knows the properties of the elements around it

2.
Alternative periodic tables
–
Alternative periodic tables are tabulations of chemical elements differing significantly in their organization from the traditional depiction of the periodic system. Several have been devised, often purely for reasons, as not all correlations between the chemical elements are effectively captured by the standard periodic table. Alternative periodic tables are developed often to highlight or emphasize different chemical or physical properties of the elements which are not as apparent in traditional periodic tables, some tables aim to emphasize both the nucleon and electronic structure of atoms. This can be done by changing the relationship or representation each element has with respect to another element in the table. Other tables aim to emphasize the chemical element isolations by humans over time, charles Janets Left step periodic table is considered to be the most significant alternative to the traditional depiction of the periodic system. It organizes elements according to orbital filling and is used by physicists. For example, most of the row in the standard table is the fifth row in this table. A modern version of the table is constructed by Valery Tsimmerman. Its structure is based on the four numbers of the electron configuration. A superactinide island is already slotted in, the Chemical Galaxy is organized in a similar way. Timothy Stowes physicists periodic table is three-dimensional with the three representing the principal quantum number, orbital quantum number, and orbital magnetic quantum number. Helium is again a group 2 element, paul Giguères 3-D periodic table consists of 4 connected billboards with the elements written on the front and the back. The first billboard has the group 1 elements on the front, at a 90° angle the second billboard contains the groups 13 to 18 front and back. Two more billboard each making 90° angles contain the other elements, rich has proposed a periodic table where elements appear more than once when appropriate. In this rendition of the periodic table carbon and silicon also appear in the group as titanium and zirconium. A chemists table with a positioning of hydrogen, helium. From Mendeleevs original periodic table, elements have been arranged by valence. Over the years and with discoveries in atomic structure, this schema has been adjusted and expanded, the oldest periodic table is the short form table by Dmitri Mendeleev, which shows secondary chemical kinships

3.
Chemical Galaxy
–
John Drury Clark was the first to present a spiral with an oval outline. His design was used as a vividly coloured two-page illustration in Life magazine for 16 May 1949. In 1951, Edgar Longman, an artist, not a chemist, painted a mural, adapting the Life image by making the shape elliptical. This inspired Stewart, then 12 years old, with a love of chemistry, having just read Fred Hoyles book The Nature of the Universe, he had the idea that Longmans design resembled a spiral galaxy. He returned to the many years later and published a first version of his galaxy in November 2004. A revised version, Chemical Galaxy II, introduces a new scheme, inspired by Michael Laing, for coloring the lanthanides and actinides, the design was translated into digital form by Carl Wenczek of Born Digital Ltd. A new image of the periodic table, a century on from Dmitrii Mendeleev, tables and spirals, noble gases and Nobel prizes. The past and future of the periodic table

4.
History of the periodic table
–
The periodic table is an arrangement of the chemical elements, organized on the basis of their atomic numbers, electron configurations and recurring chemical properties. Elements are presented in order of increasing atomic number, the standard form of the table consists of a grid of elements, with rows called periods and columns called groups. The history of the table reflects over a century of growth in the understanding of chemical properties. A number of elements have been known from antiquity, as they are found in their native form and are relatively simple to mine with primitive tools. The four roots, which were renamed as elements by Plato, were earth, water, air. Similar ideas about these four elements also existed in ancient traditions. While Aristotle and Plato understood the concept of an element, their ideas did nothing to advance the understanding of the nature of matter, the history of the periodic table is also a history of the discovery of the chemical elements. The first person in history to discover a new element was Hennig Brand, Brand tried to discover the Philosophers Stone — a mythical object that was supposed to turn inexpensive base metals into gold. In 1649, his experiments with distilled human urine resulted in the production of a white substance. He kept his secret until 1680, when Robert Boyle rediscovered phosphorus. The discovery of phosphorus helped to raise the question of what it meant for a substance to be an element, in 1661, Boyle defined an element as a substance that cannot be broken down into a simpler substance by a chemical reaction. This simple definition served for three centuries and lasted until the discovery of subatomic particles, Lavoisiers Traité Élémentaire de Chimie, which was written in 1789 and first translated into English by the writer Robert Kerr, is considered to be the first modern textbook about chemistry. Lavoisiers list also included light and caloric, which at the time were believed to be material substances and he has classified these substances into metals and non metals. While many leading chemists refused to believe Lavoisiers new revelations, the Elementary Treatise was written well enough to convince the younger generation, however, Lavoisiers descriptions of his elements lack completeness, as he only classified them as metals and non-metals. In 1817, Johann Wolfgang Döbereiner began to formulate one of the earliest attempts to classify the elements, in 1829, he found that he could form some of the elements into groups of three, with the members of each group having related properties. In 1862 he devised a form of periodic table, which he named Vis tellurique, after the element tellurium. With the elements arranged in a spiral on a cylinder by order of increasing atomic weight and his 1863 publication included a chart, but his original paper in the Comptes rendus de lAcadémie des sciences used geological rather than chemical terms and did not include a diagram. As a result, de Chancourtois ideas received little attention until after the work of Dmitri Mendeleev had been publicised, in 1864, the English chemist John Newlands classified the sixty-two known elements into eight groups, based on their physical properties

5.
Dmitri Mendeleev
–
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. Mendeleev was born in the village of Verkhnie Aremzyani, near Tobolsk in Siberia, to Ivan Pavlovich Mendeleev and his grandfather was Pavel Maximovich Sokolov, a priest of the Russian Orthodox Church from the Tver region. Ivan, along with his brothers and sisters, obtained new family names while attending the theological seminary, Mendeleev was raised as an Orthodox Christian, his mother encouraging him to patiently search divine and scientific truth. His son would later inform that he departed from the Church, Mendeleev is thought to be the youngest of either 11,13,14 or 17 siblings, the exact number differs among sources. His father was a teacher of arts, politics and philosophy. Unfortunately for the familys financial well being, his father became blind and his mother was forced to work and she restarted her familys abandoned glass factory. At the age of 13, after the passing of his father, in 1849, his mother took Mendeleev across the entire state of Russia from Siberia to Moscow with the aim of getting Mendeleev a higher education. The university in Moscow did not accept him, the mother and son continued to St. Petersburg to the father’s alma mater. The now poor Mendeleev family relocated to Saint Petersburg, where he entered the Main Pedagogical Institute in 1850, after graduation, he contracted tuberculosis, causing him to move to the Crimean Peninsula on the northern coast of the Black Sea in 1855. While there he became a master of the Simferopol gymnasium №1. In 1857, he returned to Saint Petersburg with fully restored health, between 1859 and 1861, he worked on the capillarity of liquids and the workings of the spectroscope in Heidelberg. Later in 1861, he published a textbook named Organic Chemistry and this won him the Demidov Prize of the Petersburg Academy of Sciences. On 4 April 1862 he became engaged to Feozva Nikitichna Leshcheva, Mendeleev became a professor at the Saint Petersburg Technological Institute and Saint Petersburg State University in 1864, and 1865, respectively. In 1865 he became Doctor of Science for his dissertation On the Combinations of Water with Alcohol and he achieved tenure in 1867 at St. Petersburg University and started to teach inorganic chemistry, while succeeding Voskresenskii to this post. And by 1871 he had transformed Saint Petersburg into a recognized center for chemistry research. In 1876, he became obsessed with Anna Ivanova Popova and began courting her, in 1881 he proposed to her and his divorce from Leshcheva was finalized one month after he had married Popova in early 1882. Even after the divorce, Mendeleev was technically a bigamist, the Russian Orthodox Church required at least seven years before lawful remarriage and his divorce and the surrounding controversy contributed to his failure to be admitted to the Russian Academy of Sciences. His daughter from his marriage, Lyubov, became the wife of the famous Russian poet Alexander Blok

6.
Chemical elements in East Asian languages
–
The names for chemical elements in East Asian languages, along with those for some chemical compounds, are among the newest words to enter the local vocabularies. While most East Asian languages use—or have used—the Chinese script, only the Chinese language uses the characters as the predominant way of naming elements, on the other hand, the Japanese, Koreans and Vietnamese primarily employ native alphabets for the names of the elements. In Chinese, characters for the elements are the last officially created and recognized characters in the Chinese writing system, new names and symbols are decided upon by the China National Committee for Terms in Sciences and Technologies. Some metallic elements were already familiar to the Chinese, as their ores were already excavated and used extensively in China for construction, alchemy, and medicine. These include the group of Five Metals — gold, silver, copper, iron. Some non-metals were already named in Chinese as well, because their minerals were in widespread use, for example, carbon in the form of charcoal boron as part of borax sulfur had been used to make gunpowder since at least the 10th century in China. However, the Chinese did not know about most of the elements until they were isolated during the Industrial Age and these new elements therefore required new characters, which were invented using the phono-semantic principle. Each character consists of two parts, one to signify the meaning and the other to hint at the sound and it refers to the elements usual state at room temperature and standard pressure. There are only four used for elements, 釒/钅 for solid metals, 石 for solid non-metals, 水/氵 for liquids. The phonetic part represents the pronunciation and is a partial transliteration of the element. For each element character, this is a phonetic component. Since there are over 100 elements already discovered, there are over 100 different phonetic components used in naming the elements, † 內/内 is primarily pronounced as nèi, but has less commonly as nà, the source of 納/纳. Likewise, the pronunciation of 弟 is dì, but the alternate reading of tì gave rise to 悌. * The derived pronunciation differs from the pronunciation of the element, the water radical is rarely used, since only two elements are truly liquid at standard room temperature and pressure. Both of their characters are not based on the European pronunciation of the elements names, bromine, the only liquid nonmetal at room temperature, is explained in the following section. Mercury, now grouped with the metals, was long classified as a kind of fluid in ancient China. A few characters, though, are not created using the above phono-semantic design, but are semantic-semantic, one part refers to the elements usual state, while the other part indicates some additional property or function of the element. In addition, the part also indicates the pronunciation of the element

7.
Group (periodic table)
–
In chemistry, a group is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the table, but the f-block columns are not numbered. There are three systems of group numbering, the modern numbering group 1 to group 18 is recommended by the International Union of Pure and Applied Chemistry. It replaces two older naming schemes that were mutually confusing, also, groups may be identified by their topmost element or have a specific name. For example, group 16 is variously described as oxygen group, two earlier group number systems exist, CAS and old IUPAC. Both use numerals and letters A and B, both systems agree on the numbers. The numbers indicate approximately the highest oxidation number of the elements in that group, the number proceeds in a linearly increasing fashion for the most part, once on the left of the table, and once on the right, with some irregularities in the transition metals. However, the two use the letters differently. For example, potassium has one valence electron, therefore, it is located in group 1. Calcium is in group 2, for it contains two valence electrons, the old IUPAC system was frequently used in Europe while the CAS is most common in America. The new IUPAC scheme was developed to both systems as they confusingly used the same names to mean different things. The new system simply numbers the groups increasingly from left to right on the periodic table. The IUPAC proposal was first circulated in 1985 for public comments, in history, several sets of group names have been used, Scerri, E. R. The periodic table, its story and its significance

8.
Alkali metal
–
The alkali metals are a group in the periodic table consisting of the chemical elements lithium, sodium, potassium, rubidium, caesium, and francium. Indeed, the alkali metals provide the best example of trends in properties in the periodic table. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and they can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation by atmospheric moisture and oxygen. Because of their reactivity, they must be stored under oil to prevent reaction with air. Caesium, the alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the alkali metals reacting more vigorously than the lighter ones. Experiments have been conducted to attempt the synthesis of ununennium, which is likely to be the member of the group. Most alkali metals have different applications. One of the applications of the pure elements is the use of rubidium and caesium in atomic clocks, of which caesium atomic clocks are the most accurate. A common application of the compounds of sodium is the sodium-vapour lamp, table salt, or sodium chloride, has been used since antiquity. The physical and chemical properties of the alkali metals can be explained by their having an ns1 valence electron configuration. Hence, all the metals are soft and have low densities, melting and boiling points, as well as heats of sublimation, vaporisation. They all crystallise in the cubic crystal structure, and have distinctive flame colours because their outer s electron is very easily excited. The ns1 configuration also results in the alkali metals having very large atomic and ionic radii, most of the chemistry has been observed only for the first five members of the group. The chemistry of francium is not well established due to its radioactivity, thus. What little is known about francium shows that it is close in behaviour to caesium. The physical properties of francium are even sketchier because the element has never been observed. The alkali metals are more similar to other than the elements in any other group are to each other

9.
Alkaline earth metal
–
The alkaline earth metals are six chemical elements in column 2 of the Periodic table. They are beryllium, magnesium, calcium, strontium, barium, the elements have very similar properties, they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. All the discovered alkaline earth metals occur in nature, experiments have been conducted to attempt the synthesis of element 120, the next potential member of the group, but they have all met with failure. The chemistry of radium is not well-established due to its radioactivity, thus, the alkaline earth metals are all silver-colored and soft, and have relatively low densities, melting points, and boiling points. In chemical terms, all of the alkaline metals react with the halogens to form the earth metal halides. All the alkaline earth metals except beryllium also react with water to form strongly alkaline hydroxides and, thus, the heavier alkaline earth metals react more vigorously than the lighter ones. The second ionization energy of all of the metals is also somewhat low. Beryllium is an exception, It does not react with water or steam, all compounds that include beryllium have a covalent bond. Even the compound beryllium fluoride, which is the most ionic beryllium compound, has a low melting point and a low electrical conductivity when melted. The alkaline earth metals all react with the halogens to form ionic halides, such as calcium chloride, calcium, strontium, and barium react with water to produce hydrogen gas and their respective hydroxides, and also undergo transmetalation reactions to exchange ligands. The table below is a summary of the key physical and atomic properties of the alkaline earth metals, calcium-48 is the lightest nuclide to undergo double beta decay. The natural radioisotope of calcium, calcium-48, makes up about 0. 1874% of natural calcium, barium-130 makes up approximately 0. 1062% of natural barium, and, thus, barium is weakly radioactive, as well. The alkaline earth metals are named after their oxides, the alkaline earths, whose old-fashioned names were beryllia, magnesia, lime, strontia and these oxides are basic when combined with water. Earth is an old term applied by early chemists to nonmetallic substances that are insoluble in water, the realization that these earths were not elements but compounds is attributed to the chemist Antoine Lavoisier. In his Traité Élémentaire de Chimie of 1789 he called them salt-forming earth elements, later, he suggested that the alkaline earths might be metal oxides, but admitted that this was mere conjecture. The calcium compounds calcite and lime have been known and used since prehistoric times, the same is true for the beryllium compounds beryl and emerald. The other compounds of the alkaline earth metals were discovered starting in the early 15th century, the magnesium compound magnesium sulfate was first discovered in 1618 by a farmer at Epsom in England. Strontium carbonate was discovered in minerals in the Scottish village of Strontian in 1790, the last element is the least abundant, radioactive radium, which was extracted from uraninite in 1898

10.
Group 3 element
–
Group 3 is a group of elements in the periodic table. This group, like other groups, should contain four elements. When the group is understood to contain all of the lanthanides, three group 3 elements occur naturally, scandium, yttrium, and either lanthanum or lutetium. Lanthanum continues the trend started by two members in general chemical behavior, while lutetium behaves more similarly to yttrium. They all are silvery-white metals under standard conditions, the fourth element, either actinium or lawrencium, has only radioactive isotopes. So far, no experiments have been conducted to synthesize any element that could be the next group 3 element, in 1787, Swedish part-time chemist Carl Axel Arrhenius found a heavy black rock near the Swedish village of Ytterby, Sweden. Thinking that it was a mineral containing the newly discovered element tungsten. Finnish scientist Johan Gadolin identified a new oxide or earth in Arrhenius sample in 1789, and published his analysis in 1794, in 1797. Until the early 1920s, the chemical symbol Yt was used for the element, yttrium metal was first isolated in 1828 when Friedrich Wöhler heated anhydrous yttrium chloride with potassium to form metallic yttrium and potassium chloride. In 1869, Russian chemist Dmitri Mendeleev published his periodic table, Mendeleev made several predictions on the upper neighbor of yttrium, which he called eka-boron. Swedish chemist Lars Fredrik Nilson and his team discovered the element in the minerals euxenite and gadolinite. He named it scandium, from the Latin Scandia meaning Scandinavia, Nilson was apparently unaware of Mendeleevs prediction, but Per Teodor Cleve recognized the correspondence and notified Mendeleev. Metallic scandium was produced for the first time in 1937 by electrolysis of a mixture, at 700–800 °C, of potassium, lithium. In 1751, the Swedish mineralogist Axel Fredrik Cronstedt discovered a mineral from the mine at Bastnäs. Thirty years later, the fifteen-year-old Vilhelm Hisinger, from the family owning the mine, sent a sample of it to Carl Scheele, ceria was simultaneously independently isolated in Germany by Martin Heinrich Klaproth. He partially decomposed a sample of cerium nitrate by roasting it in air, since lanthanums properties differed only slightly from those of cerium, and occurred along with it in its salts, he named it from the Ancient Greek λανθάνειν. Relatively pure lanthanum metal was first isolated in 1923, Urbain chose the names neoytterbium for ytterbium and lutecium for the new element. The dispute on the priority of the discovery is documented in two articles in which Urbain and von Welsbach accuse each other of publishing results influenced by the research of the other

11.
Group 4 element
–
Group 4 is a group of elements in the periodic table. It contains the elements titanium, zirconium, hafnium and rutherfordium and this group lies in the d-block of the periodic table. The group itself has not acquired a name, it belongs to the broader grouping of the transition metals. The three Group 4 elements that occur naturally are titanium, zirconium and hafnium, the first three members of the group share similar properties, all three are hard refractory metals under standard conditions. However, the fourth element rutherfordium, has been synthesized in the laboratory, all isotopes of rutherfordium are radioactive. So far, no experiments in a supercollider have been conducted to synthesize the next member of the group, unpenthexium, the chemistry of rutherfordium is not very established and therefore the rest of the section deals only with titanium, zirconium, and hafnium. All the elements of the group are metals with a high melting point. The reactivity is not always due to the rapid formation of a stable oxide layer. The oxides TiO2, ZrO2 and HfO2 are white solids with high melting points, as tetravalent transition metals, all three elements form various inorganic compounds, generally in the oxidation state of +4. For the first three metals, it has shown that they are resistant to concentrated alkalis, but halogens react with them to form tetrahalides. At higher temperatures, all three metals react with oxygen, nitrogen, carbon, boron, sulfur, and silicon, because of the lanthanide contraction of the elements in the fifth period, zirconium and hafnium have nearly identical ionic radii. The ionic radius of Zr4+ is 79 picometers and that of Hf4+ is 78 pm and this similarity results in nearly identical chemical behavior and in the formation of similar chemical compounds. The chemistry of hafnium is so similar to that of zirconium that a separation on chemical reactions was not possible, the melting points and boiling points of the compounds and the solubility in solvents are the major differences in the chemistry of these twin elements. Titanium is considerably different from the other two owing to the effects of the lanthanide contraction, the table below is a summary of the key physical properties of the group 4 elements. The four question-marked values are extrapolated, william Gregor, Franz Joseph Muller and Martin Heinrich Klaproth independently discovered titanium between 1791 and 1795. Klaproth named it for the Titans of Greek mythology, Klaproth also discovered zirconium in the mineral zircon in 1789 and named it after the already known Zirkonerde. Dirk Coster and Georg von Hevesy were the first to search for the new element in zirconium ores, hafnium was discovered by the two in 1923 in Copenhagen, Denmark, validating the original 1869 prediction of Mendeleev. While titanium and zirconium, as relatively abundant elements, were discovered in the late 18th century and this was only partly due to hafniums relative scarcity

12.
Group 5 element
–
Group 5 is a group of elements in the periodic table. Group 5 contains vanadium, niobium, tantalum and dubnium and this group lies in the d-block of the periodic table. The group itself has not acquired a name, it belongs to the broader grouping of the transition metals. The lighter three Group 5 elements occur naturally and share similar properties, all three are hard refractory metals under standard conditions, to date, no experiments in a supercollider have been conducted to synthesize the next member of the group, either unpentpentium or unpentseptium. As unpentpentium and unpentseptium are both late period 8 elements it is unlikely that these elements will be synthesized in the near future, all the elements of the group are reactive metals with a high melting points. The reactivity is not always due to the rapid formation of a stable oxide layer. Metal oxides are generally nonreactive and act like acids rather than bases and they, however, have some unusual properties for oxides, such as high electric conductivity. All three elements form various compounds, generally in the oxidation state of +5. Lower oxidation states are known, but they are less stable. Vanadium was discovered by Andrés Manuel del Río, a Spanish-born Mexican mineralogist, after other chemists rejected his discovery of erythronium he retracted his claim. Niobium was discovered by the English chemist Charles Hatchett in 1801, tantalum was first discovered in 1802 by Anders Gustav Ekeberg. However, it was thought to be identical to niobium until 1846, pure tantalum was not produced until 1903. Dubnium was first produced in 1968 at the Joint Institute for Nuclear Research by bombarding americium-243 with neon-22, dubnium was again produced at the Lawrence Berkeley Laboratory in 1970. The names neilsbohrium and joliotium were proposed for the element, but in 1997, Vanadium is named for Vanadis, the Scandinavian goddess of love. Niobium is named for Niobe, a figure from Greek mythology, tantalum is named for Tantalus, a figure from Greek mythology. Dubnium is named for Dubna, Russia, where it was discovered, there are 160 parts per million of vanadium in the earths crust, making it the 19th most abundant element there. Soil contains on average 100 parts per million of vanadium, a typical human contains 285 parts per billion of vanadium. Over 60 vanadium ores are known, including vanadinite, patronite, there are 20 parts per million of niobium in the earths crust, making it the 33rd most abundant element there

13.
Group 6 element
–
Group 6, numbered by IUPAC style, is a group of elements in the periodic table. Its members are chromium, molybdenum, tungsten, and seaborgium and these are all transition metals and chromium, molybdenum and tungsten are refractory metals. The period 8 elements of group 6 are likely to be either unpenthexium or unpentoctium and this may not be possible, drip instability may imply that the periodic table ends at unbihexium. Neither unpenthexium nor unpentoctium have been synthesized, and it is unlikely that this will happen in the near future, group 6 must not be confused with the group with the old-style group crossed names of either VIA or VIB. That group is now called group 16, though misidentified as a lead compound with selenium and iron components, the mineral was crocoite with a formula of PbCrO4. Studying the mineral in 1797, Louis Nicolas Vauquelin produced chromium trioxide by mixing crocoite with hydrochloric acid metallic chromium by heating the oxide in a charcoal oven a year later and he was also able to detect traces of chromium in precious gemstones, such as ruby or emerald. Molybdenite—the principal ore from which molybdenum is now extracted—was previously known as molybdena, like graphite, molybdenite can be used to blacken a surface or as a solid lubricant. Even when molybdena was distinguishable from graphite, it was confused with a galena. It was not until 1778 that Swedish chemist Carl Wilhelm Scheele realized that molybdena was neither graphite nor lead and he and other chemists then correctly assumed that it was the ore of a distinct new element, named molybdenum for the mineral in which it was discovered. Peter Jacob Hjelm successfully isolated molybdenum by using carbon and linseed oil in 1781, regarding tungsten, in 1781 Carl Wilhelm Scheele discovered that a new acid, tungstic acid, could be made from scheelite. Scheele and Torbern Bergman suggested that it might be possible to obtain a new metal by reducing this acid, in 1783, José and Fausto Elhuyar found an acid made from wolframite that was identical to tungstic acid. Later that year, in Spain, the brothers succeeded in isolating tungsten by reduction of this acid with charcoal, during the 1800s, chromium was primarily used as a component of paints and in tanning salts. At first, crocoite from Russia was the source, but in 1827. This made the United States the largest producer of products until 1848 when large deposits of chromite where found near Bursa. Chromium was used for electroplating as early as 1848, but this use only became widespread with the development of a process in 1924. For about a century after its isolation, molybdenum had no use, owing to its relative scarcity, difficulty extracting the pure metal. Early molybdenum steel alloys showed great promise in their increased hardness, but efforts were hampered by inconsistent results, in 1913, Frank E. Elmore developed a flotation process to recover molybdenite from ores, flotation remains the primary isolation process. During the first World War, demand for molybdenum spiked, it was used both in armor plating and as a substitute for tungsten in high speed steels, some British tanks were protected by 75 mm manganese steel plating, but this proved to be ineffective

14.
Group 7 element
–
Group 7, numbered by IUPAC nomenclature, is a group of elements in the periodic table. They are manganese, technetium, rhenium, and bohrium, all known elements of group 7 are transition metals. Like other groups, the members of family show patterns in their electron configurations. Bohrium has not been isolated in pure form, and its properties have not been observed, only manganese, technetium. All three elements are typical silvery-white transition metals, hard, and have melting and boiling points. Group 7 contains the two naturally occurring transition metals discovered last, technetium and rhenium, manganese was discovered much earlier owing to its much larger abundance in nature. Technetium was formally discovered in December 1936 by Carlo Perrier and Emilio Segré, bohrium was discovered in 1981 by a team led by Peter Armbruster and Gottfried Münzenburg by bombarding Bismuth-209 with Chromium-54. Manganese is the only common Group 7 element, in 200711 million metric tons of manganese were mined. All other elements are either incredibly rare on earth or completely synthetic, in contrast to manganese, only 40 or 50 metric tons of rhenium were mined. Technetium is only found in trace amounts in nature as a product of spontaneous fission, bohrium is only produced in nuclear reactors and has never been isolated in pure form. Although being an essential element in the human body, manganese can be somewhat toxic if ingested in higher amounts than normal. Technetium should be handled with care due to its radioactivity, only manganese has a role in the human body. It is a trace nutrient, with the body containing approximately 10 milligrams at any given time, being mainly in the liver. Many enzymes contain manganese, making it essential for life, and is found in chloroplasts. Technetium, rhenium, and bohrium have no known biological roles, technetium is however used in radioimaging

15.
Group 8 element
–
Group 8 is a group of chemical element in the periodic table. It consists of iron, ruthenium, osmium and hassium, like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior. Group 8 is the modern IUPAC name for group, the old style name was group VIIIB in the CAS, US system or group VIIIA in the old IUPAC. Group 8 should not be confused with the group name of VIIIA by CAS/US naming. That group is now called group 18, hassium has not been isolated in macroscopic pure form, and its properties have not been conclusively observed, only iron, ruthenium, and osmium have had their properties experimentally confirmed. All three elements are typical silvery-white transition metals, hard, and have melting and boiling points. Iron has been known and used to make tools since antiquity, ruthenium was first identified in 1844 in platinum ores, after all other platinum group metals, including Osmium, which was discovered in 1803, by dissolving impure platinum, salts were created. In a graphite-like dust always found in these salts, it was concluded that a new metal must be present, ruthenium was first discovered in the form of ruthenium oxide in a similar manner. Hassium was discovered in 1984 by a led by Peter Armbruster. Iron is the most common element within the earth, most of the core is iron and there is a substantial amount of iron in the mantle. Ruthenium and osmium are two of the rarest elements on earth, with ruthenium only found in small amounts in platinum ores, Osmium is the least abundant stable element in the earths crust, only found in minor traces in platinum ores. Hassium is only produced in reactors and has never been observed in nature nor isolated in pure form. Iron is a nutrient for all living organisms, from archaea to humans. It is a component in hemoglobin, a protein that makes blood red and transfers oxygen to muscles. Ruthenium, osmium, and hassium have no role in the human body

16.
Group 9 element
–
Group 9, numbered by IUPAC nomenclature, is a group of chemical element in the periodic table. Members are cobalt, rhodium, iridium and perhaps also the chemically uncharacterized meitnerium and these are all transition metals in the d-block. All known isotopes of meitnerium are radioactive with short half-lives, and it is not known to occur in nature, only minute quantities have been synthesized in laboratories. Meitnerium has not been isolated in pure form, and its properties have not been observed, only cobalt, rhodium. All three elements are typical silvery-white transition metals, hard, and have melting and boiling points. Cobalt has been discovered in Egyptian and Persian artifacts from before the 2nd millennium BCE, rhodium was discovered in 1803 when William Hyde Wollaston dissolved platinum ore in aqua regia, then neutralized the acid with sodium hydroxide. Wollaston then added ammonium chloride, and dissolved all metals except rhodium and palladium with the acid in the aqua regia. Iridium was discovered in a similar way in 1804 by Smithson Tennant. Meitnerium was discovered in 1982 by bombarding bismuth-209 with iron-58, all group 9 elements are relatively rare in the earths crust, with the most abundant, cobalt, only accounting for 0. 0029% of the Earths crust. Rhodium and iridium are two of the rarest naturally occurring elements in the earth, only found in platinum ores, meitnerium has only been produced in nuclear reactors and has never been observed in nature nor isolated in pure form. Cobalt is a trace nutrient to all animals, found in vitamin B-12. Rhodium, iridium, and meitnerium have no known biological roles, alloys with other metals, primarily to add corrosion and wear resistance Industrial Catalysts Superalloys Electrical Components Platinum group

17.
Group 10 element
–
All known isotopes of darmstadtium are radioactive with short half-lives, and are not known to occur in nature, only minute quantities have been synthesized in laboratories. Darmstadtium has not been isolated in pure form, and its properties have not been observed, only nickel, palladium. All three elements are typical silvery-white transition metals, hard, and refractory, with melting and boiling points. The existence of a +3 state is debated, as the state could be a state created by +2. Theory suggests that group 10 metals may produce a +6 oxidation state under precise conditions, the group 10 metals share several uses. These include, Decorative purposes, in the form of jewelry, catalysts in a variety of chemical reactions. Electrical components, due to their changes in electrical resistivity with regard to temperature. Superconductors, as components in alloys with other metals, nickel has an important role in the biochemistry of organisms, as part of the active center of enzymes. None of the other group 10 elements have a biological role. Aside from nickel, the elements are toxic for organisms

18.
Group 11 element
–
Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper, silver, and gold. Roentgenium is also placed in group in the periodic table. Group 11 is also known as the metals, due to their former usage. They were most likely the first three elements discovered, Copper, silver, and gold all occur naturally in elemental form. All the elements of the group except roentgenium have been known since prehistoric times, as all of them occur in metallic form in nature and these elements have low electrical resistivity so they are used for wiring. Copper is the cheapest and most widely used, bond wires for integrated circuits are usually gold. Silver and silver-plated copper wiring are found in special applications. Copper occurs in its form in Chile, China, Mexico, Russia. Various natural ores of copper are, copper pyrites, cuprite or ruby copper, copper glance, malachite, Copper pyrite is the principal ore, and yields nearly 76% of the world production of copper. Silver is found in form, as an alloy with gold. Ores include argentite, chlorargyrite which includes horn silver, and pyrargyrite, silver is extracted using the Parkes process. These metals, especially silver, have properties that make them essential for industrial applications outside of their monetary or decorative value. They are all excellent conductors of electricity, the most conductive of all metals are silver, copper and gold in that order. Silver is also the most thermally conductive element, and the most light reflecting element, silver also has the unusual property that the tarnish that forms on silver is still highly electrically conductive. Copper is used extensively in electrical wiring and circuitry, Gold contacts are sometimes found in precision equipment for their ability to remain corrosion-free. Silver is used widely in mission-critical applications as electrical contacts, and is used in photography, agriculture, medicine, audiophile. Gold, silver, and copper are quite soft metals and so are easily damaged in use as coins. Precious metal may also be easily abraded and worn away through use, in their numismatic functions these metals must be alloyed with other metals to afford coins greater durability

19.
Group 12 element
–
Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc, cadmium and mercury, the further inclusion of copernicium in group 12 is supported by recent experiments on individual copernicium atoms. Group 12 is also known as the metals, although this can also more generally refer to any metal that has high volatility. Formerly this group was named IIB by CAS and old IUPAC system, the three group 12 elements that occur naturally are zinc, cadmium and mercury. They are all used in electric and electronic applications, as well as in various alloys. The first two members of the group share similar properties as they are solid metals under standard conditions, Mercury is the only metal that is a liquid at room temperature. While zinc is very important in the biochemistry of living organisms, cadmium, as copernicium does not occur in nature, it has to be synthesized in the laboratory. They have the lowest melting points among all transition metals, zinc is bluish-white and lustrous, though most common commercial grades of the metal have a dull finish. Zinc is also referred to in nonscientific contexts as spelter, cadmium is soft, malleable, ductile, and with a bluish-white color. Mercury is a liquid, heavy, silvery-white metal and it is the only common liquid metal at ordinary temperatures, and as compared to other metals, it is a poor conductor of heat, but a fair conductor of electricity. The table below is a summary of the key properties of the group 12 elements. Very little is known about copernicium, and none of its properties have been confirmed except for its boiling point. Zinc is somewhat less dense than iron and has a crystal structure. The metal is hard and brittle at most temperatures but becomes malleable between 100 and 150 °C, above 210 °C, the metal becomes brittle again and can be pulverized by beating. Zinc is a conductor of electricity. For a metal, zinc has relatively low melting and boiling points, cadmium is similar in many respects to zinc but forms complex compounds. Unlike other metals, cadmium is resistant to corrosion and as a result it is used as a protective layer when deposited on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable, however, in its form it may burn

20.
Boron group
–
The boron group are the chemical elements in group 13 of the periodic table, comprising boron, aluminium, gallium, indium, thallium, and perhaps also the chemically uncharacterized nihonium. The elements in the group are characterized by having three electrons in their outer energy levels. These elements have also referred to as icosagens and triels. Boron is classified as a metalloid while the rest, with the exception of nihonium, are considered post-transition metals. Boron occurs sparsely, probably because bombardment by the particles produced from natural radioactivity disrupts its nuclei. Aluminium occurs widely on earth, and indeed is the third most abundant element in the Earths crust, gallium is found in the earth with an abundance of 13 ppm. Indium is the 61st most abundant element in the earths crust, nihonium is never found in nature and therefore is termed a synthetic element. Several group 13 elements have biological roles in the ecosystem, Boron is a trace element in humans and is essential for some plants. Lack of boron can lead to stunted plant growth, while an excess can cause harm by inhibiting growth. Aluminium has neither a biological role nor significant toxicity and is considered safe, indium and gallium can stimulate metabolism, gallium is credited with the ability to bind itself to iron proteins. Thallium is highly toxic, interfering with the function of numerous vital enzymes, Boron differs from the other group members in its hardness, refractivity and reluctance to participate in metallic bonding. An example of a trend in reactivity is borons tendency to form compounds with hydrogen. Most of the elements in the group show increasing reactivity as the elements get heavier in atomic mass. The simplest borane is diborane, or B2H6, the next group-13 elements, aluminium and gallium, form fewer stable hydrides, although both AlH3 and GaH3 exist. Indium, the element in the group, is not known to form many hydrides. No stable compound of thallium and hydrogen has been synthesized in any laboratory, all of the boron-group elements are known to form a trivalent oxide, with two atoms of the element bonded covalently with three atoms of oxygen. These elements show a trend of increasing pH, Boron oxide is slightly acidic, aluminium and gallium oxide are amphoteric, indium oxide is nearly amphoteric, and thallium oxide is a Lewis base because it dissolves in acids to form salts. Each of these compounds are stable, but thallium oxide decomposes at temperatures higher than 875 °C, the elements in group 13 are also capable of forming stable compounds with the halogens, usually with the formula MX3 The only exception to this is thallium iodide

21.
Carbon group
–
The carbon group is a periodic table group consisting of carbon, silicon, germanium, tin, lead, and flerovium. In modern IUPAC notation, it is called Group 14, in the field of semiconductor physics, it is still universally called Group IV. The group was also known as the tetrels, stemming from the Roman numeral IV in the group names. The group is also referred to as tetragens because it has four electrons in its outermost shell or the valence shell. This group is called the crystallogens. The last orbital of all elements is the p2 orbital. In most cases, the elements share their electrons, the tendency to lose electrons increases as the size of the atom increases, as it does with increasing atomic number. Carbon alone forms negative ions, in the form of carbide ions, silicon and germanium, both metalloids, each can form +4 ions. Tin and lead both are metals while flerovium is a synthetic, radioactive, element that may have a few noble gas-like properties, tin and lead are both capable of forming +2 ions. Carbon forms tetrahalides with all the halogens, carbon also forms three oxides, carbon monoxide, carbon suboxide, and carbon dioxide. Silicon forms two hydrides, SiH4 and Si2H6, silicon forms tetrahalides with fluorine, chlorine, and iodine. Silicon also forms a dioxide and a disulfide, silicon nitride has the formula Si3N4. Germanium forms two hydrides, GeH4 and Ge2H6, germanium forms tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine. Germanium bonds to all natural single chalcogens except polonium, and forms dioxides, disulfides, germanium nitride has the formula Ge3N4. Tin forms two hydrides, SnH4 and Sn2H6, tin forms dihalides and tetrahalides with all halogens except astatine. Tin forms chalcogenides with one of each naturally occurring chalcogen except polonium, lead forms one hydride, which has the formula PbH4. Lead forms dihalides and tetrahalides with fluorine and chlorine, and forms a tetrabromide, lead forms four oxides, a sulfide, a selenide, and a telluride. There are no known compounds of flerovium, the boiling points of the carbon group tend to get lower with the heavier elements

22.
Pnictogen
–
A pnictogen /ˈnɪktədʒᵻn/ is one of the chemical elements in group 15 of the periodic table. This group is known as the nitrogen family. It consists of the nitrogen, phosphorus, arsenic, antimony, bismuth. In modern IUPAC notation, it is called Group 15, in CAS and the old IUPAC systems it was called Group VA and Group VB respectively. In the field of physics, it is still usually called Group V. The five in the names comes from the pentavalency of nitrogen. The term pnictogen is derived from the Ancient Greek word πνίγειν meaning to choke and they are therefore 3 electrons short of filling their outermost electron shell in their non-ionized state. The most important elements of group are nitrogen, which in its diatomic form is the principal component of air, and phosphorus. Binary compounds of the group can be referred to collectively as pnictides, the name pentels was also used for this group at one time, stemming from the earlier group naming convention. Pnictide compounds tend to be exotic, various properties that some pnictides have include being diamagnetic and paramagnetic at room temperature, being transparent, and generating electricity when heated. Other pnictides include the ternary rare-earth main-group variety of pnictides and these are in the form of REaMbPnc, where M is a carbon group or boron group element and Pn is any pnictogen except nitrogen. These compounds are ionic and covalent compounds and thus have unusual bonding properties. These elements are noted for their stability in compounds due to their tendency for forming double and triple covalent bonds. This is the property of these elements which leads to their toxicity, most evident in phosphorus, arsenic. When these substances react with various chemicals of the body, they create strong free radicals not easily processed by the liver, where they accumulate. For example, N2, the form of nitrogen, is used as an inert gas in situations where using argon or another noble gas would be too expensive. The upper pnictogens, that is, nitrogen, phosphorus, Antimony and bismuth can either take on a +3 or +5, by losing its p-shell electrons or losing its p-shell and s-shell electrons, respectively. Pnictogens can react with hydrogen to form pnictogen hydrides such as ammonia, the pnictogens consist of two nonmetals, two metalloids, one metal, and one element with unknown chemical properties

23.
Chalcogen
–
The chalcogens are the chemical elements in group 16 of the periodic table. This group is known as the oxygen family. It consists of the oxygen, sulfur, selenium, tellurium. The chemically uncharacterized synthetic element livermorium is predicted to be a chalcogen as well, the word chalcogen is derived from a combination of the Greek word khalkόs principally meaning copper, and the Latinised Greek word genēs, meaning born or produced. Sulfur has been known since antiquity, and oxygen was recognized as an element in the 18th century, selenium, tellurium and polonium were discovered in the 19th century, and livermorium in 2000. All of the chalcogens have six valence electrons, leaving them two electrons short of an outer shell. Their most common oxidation states are −2, +2, +4 and they have relatively low atomic radii, especially the lighter ones. Lighter chalcogens are typically nontoxic in their form, and are often critical to life. All of the chalcogens have some role in functions, either as a nutrient or a toxin. The lighter chalcogens, such as oxygen and sulfur, are rarely toxic, selenium is an important nutrient but is also commonly toxic. Tellurium often has unpleasant effects, and polonium is always extremely harmful, sulfur has more than 20 allotropes, oxygen has nine, selenium has at least five, polonium has two, and only one crystal structure of tellurium has so far been discovered. There are numerous organic chalcogen compounds, not counting oxygen, organic sulfur compounds are generally the most common, followed by organic selenium compounds and organic tellurium compounds. This trend also occurs with chalcogen pnictides and compounds containing chalcogens, oxygen is generally extracted from air and sulfur is extracted from oil and natural gas. Selenium and tellurium are produced as byproducts of copper refining, polonium and livermorium are most available in particle accelerators. The primary use of oxygen is in steelmaking. Sulfur is mostly converted into sulfuric acid, which is used in the chemical industry. Seleniums most common application is glassmaking, tellurium compounds are mostly used in optical disks, electronic devices, and solar cells. Some of poloniums applications are due to its radioactivity, all of the solid, stable chalcogens are soft and do not conduct heat well

24.
Halogen
–
The halogens or halogen elements are a group in the periodic table consisting of five chemically related elements, fluorine, chlorine, bromine, iodine, and astatine. The artificially created element 117 may also be a halogen, in the modern IUPAC nomenclature, this group is known as group 17. The symbol X is often used generically to refer to any halogen, when halogens react with metals they produce a wide range of salts, including calcium fluoride, sodium chloride, silver bromide and potassium iodide. The group of halogens is the periodic table group that contains elements in three of the four main states of matter at standard temperature and pressure. All of the halogens form acids when bonded to hydrogen, most halogens are typically produced from minerals or salts. The middle halogens, that is chlorine, bromine and iodine, are used as disinfectants. Organobromides are the most important class of flame retardants, elemental halogens are dangerously to potentially lethally toxic. The fluorine mineral fluorospar was known as early as 1529, early chemists realized that fluorine compounds contain an undiscovered element, but were unable to isolate it. In 1869, George Gore, an English chemist, ran a current of electricity through hydrofluoric acid and discovered fluorine, in 1886, Henri Moissan, a chemist in Paris, performed electrolysis on potassium bifluoride dissolved in waterless hydrofluoric acid, and successfully produced fluorine. Hydrochloric acid was known to alchemists and early chemists, However, elemental chlorine was not produced until 1774, when Carl Wilhelm Scheele heated hydrochloric acid with manganese dioxide. Scheele called the element dephlogisticated muriatic acid, which is how chlorine was known for 33 years, in 1807, Humphry Davy investigated chlorine and discovered that it is an actual element. Chlorine was used as a poison gas during World War I, bromine was discovered in the 1820s by Antoine-Jérôme Balard. Balard discovered bromine by passing gas through a sample of brine. He originally proposed the name muride for the new element, iodine was discovered by Bernard Courtois, who was using seaweed ash as part of a process for saltpeter manufacture. Courtois typically boiled the seaweed ash with water to generate potassium chloride, However, in 1811, Courtois added sulfuric acid to his process, and found that his process produced purple fumes that condensed into black crystals. Suspecting that these crystals were a new element, Courtois sent samples to other chemists for investigation, iodine was proven to be a new element by Joseph Gay-Lussac. In 1931, Fred Allison claimed to have discovered element 85 with a machine, and named the element Alabamine. In 1937, Jajendralal De claimed to have discovered element 85 in minerals, and called the element dakine, element 85, now named astatine, was produced successfully in 1940 by Dale R. Corson, K. R

25.
Noble gas
–
The noble gases make a group of chemical elements with similar properties, under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are helium, neon, argon, krypton, xenon, oganesson is predicted to be a noble gas as well, but its chemistry has not yet been investigated. For the first six periods of the table, the noble gases are exactly the members of group 18 of the periodic table. Noble gases are typically highly unreactive except when under particular extreme conditions, the inertness of noble gases makes them very suitable in applications where reactions are not wanted. The melting and boiling points for a noble gas are close together, differing by less than 10 °C. Neon, argon, krypton, and xenon are obtained from air in an air separation unit using the methods of liquefaction of gases, Noble gases have several important applications in industries such as lighting, welding, and space exploration. After the risks caused by the flammability of hydrogen became apparent, it was replaced with helium in blimps, Noble gas is translated from the German noun Edelgas, first used in 1898 by Hugo Erdmann to indicate their extremely low level of reactivity. The name makes an analogy to the noble metals, which also have low reactivity. The noble gases have also referred to as inert gases. Rare gases is another term that was used, but this is inaccurate because argon forms a fairly considerable part of the Earths atmosphere due to decay of radioactive potassium-40. Pierre Janssen and Joseph Norman Lockyer discovered a new element on August 18,1868 while looking at the chromosphere of the Sun, no chemical analysis was possible at the time, but helium was later found to be a noble gas. Before them, in 1784, the English chemist and physicist Henry Cavendish had discovered that air contains a proportion of a substance less reactive than nitrogen. A century later, in 1895, Lord Rayleigh discovered that samples of nitrogen from the air were of a different density than nitrogen resulting from chemical reactions, with this discovery, they realized an entire class of gases was missing from the periodic table. During his search for argon, Ramsay also managed to isolate helium for the first time while heating cleveite, Ramsay continued to search for these gases using the method of fractional distillation to separate liquid air into several components. In 1898, he discovered the elements krypton, neon, and xenon, and named them after the Greek words κρυπτός, νέος, and ξένος, respectively. Rayleigh and Ramsay received the 1904 Nobel Prizes in Physics and in Chemistry, respectively, for their discovery of the noble gases, the discovery of the noble gases aided in the development of a general understanding of atomic structure. In 1895, French chemist Henri Moissan attempted to form a reaction between fluorine, the most electronegative element, and argon, one of the noble gases, but failed. Scientists were unable to prepare compounds of argon until the end of the 20th century, in 1962, Neil Bartlett discovered the first chemical compound of a noble gas, xenon hexafluoroplatinate

26.
Period (periodic table)
–
A period in the periodic table is one of the horizontal rows, all of whose elements have the same number of electron shells. Going across a period, each element has one proton and is less metallic than its predecessor. Arranged this way, groups of elements in the column have similar chemical and physical properties. For example, the alkaline metals lie in the first column and share similar properties, such as high reactivity, at the present time, the periodic table of elements has a total of 118 elements which have been discovered to date. Modern quantum mechanics explains these periodic trends in properties in terms of electron shells, as atomic number increases, shells fill with electrons in approximately the order shown at right. The filling of each corresponds to a row in the table. In the s-block and p-block of the table, elements within the same period generally do not exhibit trends. However, in the d-block, trends across periods become significant, seven periods of elements occur naturally on Earth. For period 8, which includes elements which may be synthesized after 2015, a group in chemistry means a family of objects with similarities like different families. There are 7 periods, going horizontally across the periodic table, the first period contains fewer elements than any other, with only two, hydrogen and helium. They therefore do not follow the octet rule, chemically, helium behaves as a noble gas, and thus is taken to be part of the group 18 elements. However, in terms of its structure it belongs to the s block. Hydrogen readily loses and gains an electron, and so behaves chemically as both a group 1 and a group 17 element, hydrogen is the most abundant of the chemical elements, constituting roughly 75% of the universes elemental mass. Ionized hydrogen is just a proton, stars in the main sequence are mainly composed of hydrogen in its plasma state. Elemental hydrogen is rare on Earth, and is industrially produced from hydrocarbons such as methane. Hydrogen can form compounds with most elements and is present in water, helium exists only as a gas except in extreme conditions. It is the second lightest element and is the second most abundant in the universe, most helium was formed during the Big Bang, but new helium is created through nuclear fusion of hydrogen in stars. On Earth, helium is rare, only occurring as a byproduct of the natural decay of some radioactive elements

27.
Period 1 element
–
A period 1 element is one of the chemical elements in the first row of the periodic table of the chemical elements. The first period contains fewer elements than any other row in the table and this situation can be explained by modern theories of atomic structure. In a quantum description of atomic structure, this period corresponds to the filling of the 1s orbital. Period 1 elements obey the rule in that they need two electrons to complete their valence shell. The maximum number of electrons that these elements can accommodate is two, both in the 1s orbital, therefore, period 1 can have only two elements. All other periods in the table contain at least 8 elements. However, period 1 contains only two elements, so this concept does not apply here, although both hydrogen and helium are in the s-block, neither of them behaves similarly to other s-block elements. Their behaviour is so different from the other elements that there is considerable disagreement over where these two elements should be placed in the periodic table. Helium is almost always placed above neon in the table as a noble gas. Hydrogen is the element with atomic number 1. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, with an atomic mass of 1.00794 amu, hydrogen is the lightest element. Hydrogen is the most abundant of the elements, constituting roughly 75% of the universes elemental mass. Stars in the sequence are mainly composed of hydrogen in its plasma state. Hydrogen may be produced from using the process of electrolysis. The most common naturally occurring isotope of hydrogen, known as protium, has a single proton and no neutrons. In ionic compounds, it can take on either a charge, becoming a cation composed of a bare proton, or a negative charge. Hydrogen can form compounds with most elements and is present in water and it plays a particularly important role in acid-base chemistry, in which many reactions involve the exchange of protons between soluble molecules. The interactions of hydrogen with various metals are important in metallurgy, as many metals can suffer hydrogen embrittlement

28.
Period 2 element
–
A period 2 element is one of the chemical elements in the second row of the periodic table of the chemical elements. The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and this situation can be explained by modern theories of atomic structure. In a quantum description of atomic structure, this period corresponds to the filling of the 2s. Period 2 elements obey the rule in that they need eight electrons to complete their valence shell. The maximum number of electrons that these elements can accommodate is ten, all of the elements in the period can form diatomic molecules except beryllium and neon. Period 2 is the first period in the table that periodic trends can be drawn from. Period 1, which contains two elements is too small to draw any conclusive trends from it, especially because the two elements behave nothing like other s-block elements. Period 2 has much more conclusive trends, for all elements in period 2, as the atomic number increases, the atomic radius of the elements decreases, the electronegativity increases, and the ionization energy increases. Period 2 only has two metals, making it the least metallic period and the most nonmetals, with four. All period 2 elements completely obey the Madelung rule, in period 2s, lithium and beryllium fill the 2s subshell, and boron, carbon, nitrogen, oxygen, fluorine, and neon fill the 2p subshell. The period shares this trait with periods 1 and 3, none of which contain elements or inner transition elements. Lithium is a metal with atomic number 3, occurring naturally in two isotopes, 6Li and 7Li. The two make up all natural occurrence of lithium on Earth, although further isotopes have been synthesized, in ionic compounds, lithium loses an electron to become positively charged, forming the cation Li+. Lithium is the first alkali metal in the table. At standard temperature and pressure, lithium is a soft, silver-white, with a density of 0.564 g·cm−3, lithium is the lightest metal and the least dense solid element. According to theory, Lithium is one of the few elements synthesized in the Big Bang, making it a primordial element. Lithium is the 33rd most abundant element on earth, occurring in concentrations of between 20 and 70 ppm by weight, but due to its high reactivity it is found naturally in compounds. Lithium salts are used in the industry as mood stabilising drugs

29.
Period 3 element
–
A period 3 element is one of the chemical elements in the third row of the periodic table of the chemical elements. The third period contains eight elements, sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, the first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the p-block. Note that there is a 3d subshell, but it is not filled until period 4, all of the period 3 elements occur in nature and have at least one stable isotope. As the atomic number of elements in Period 3 increases, the atomic radius decreases, as the atomic mass of elements in Period 3 increases, the electronegativity increases. As the atomic number of elements in Period 3 increases, the amount of required to remove its electrons increases. Sodium is a soft, silvery-white, highly reactive metal and is a member of the alkali metals and it is an abundant element that exists in numerous minerals such as feldspars, sodalite and rock salt. Many salts of sodium are highly soluble in water and are present in significant quantities in the Earths bodies of water. Many sodium compounds are useful, such as sodium hydroxide for soapmaking, and sodium chloride for use as a deicing agent, the free metal, elemental sodium, does not occur in nature but must be prepared from sodium compounds. Elemental sodium was first isolated by Humphry Davy in 1807 by the electrolysis of sodium hydroxide, the same ion is also a component of many minerals, such as sodium nitrate. Magnesium is an alkaline earth metal and has oxidation number +2. It is the eighth most abundant element in the Earths crust, magnesium is the fourth most common element in the Earth as a whole, making up 13% of the planets mass and a large fraction of planets mantle. The relative abundance of magnesium is related to the fact that it is built up in supernova stars from a sequential addition of three helium nuclei to carbon. Due to magnesium ions high solubility in water, it is the third most abundant element dissolved in seawater, the free element is not found naturally on Earth, as it is highly reactive. The free metal burns with a brilliant white light, making it a useful ingredient in flares. The metal is now obtained by electrolysis of magnesium salts obtained from brine. Commercially, the use for the metal is as an alloying agent to make aluminium-magnesium alloys. Since magnesium is less dense than aluminium, these alloys are prized for their relative lightness, magnesium ions are sour to the taste, and in low concentrations help to impart a natural tartness to fresh mineral waters. Aluminium or aluminum is a white member of the boron group of chemical elements

30.
Period 4 element
–
A period 4 element is one of the chemical elements in the fourth row of the periodic table of the elements. The fourth period contains 18 elements, beginning with potassium and ending with krypton, as a rule, period 4 elements fill their 4s shells first, then their 3d and 4p shells, in that order, however, there are exceptions, such as chromium. Every single one of these elements is stable, and many are common in the earths crust and/or core. Many of the metals in period 4 are incredibly strong. Copper is one of three metals that are not silver or gray in color, along with caesium and gold. Three adjacent elements are known to be toxic, with one of the most well-known poisons, selenium being toxic to humans in large quantities, and bromine. Many elements are essential to survival, such as calcium being what forms bones. Exception to the Madelung rule Potassium is an metal, placed under sodium and over rubidium. It is one of the most reactive elements in the periodic table and it tends to oxidize in air very rapidly, thus accounting for its rapid reaction with oxygen when freshly exposed to air. When freshly exposed, it is silvery, but it quickly begins to tarnish as it reacts with air. It is soft enough to be cut with a knife and it is the second least dense element, Potassium has a relatively low melting point, it will melt just by putting it under a small open flame. It also is less dense water, and can, in turn. Calcium is the element in period 4, between potassium and scandium. An alkali earth metal, calcium is almost never found in nature due to its reactivity with water. It is regarded as the most abundant mineral in the bodys mass, scandium is the third element in period 4, between calcium and titanium, and is the first transition metal in the periodic table. Scandium is quite common in nature, but difficult to find because it is most prevalent in rare earth compounds, scandium has very few commercial applications because of the aforementioned facts, and currently its only major application is in aluminium alloys. Titanium is an element in period 4, between scandium and vanadium, titanium is both one of the least dense metals and one of the strongest and most corrosion-resistant, and as such has many applications, especially in alloys with other elements, such as iron. Due to its properties, it is commonly used in airplanes, golf clubs, and other objects that must be strong

31.
Period 7 element
–
A period 7 element is one of the chemical elements in the seventh row of the periodic table of the chemical elements. The seventh period contains 32 elements, tied for the most with period 6, beginning with francium and ending with oganesson, the heaviest element currently discovered. As a rule, period 7 elements fill their 7s shells first, then their 5f, 6d, all elements of period 7 are radioactive. This period contains the actinides, which contains the heaviest naturally occurring element, plutonium, whilst the first five of these are now available in macroscopic quantities, most are extremely rare, having only been prepared in microgram amounts or less. The later, transactinide elements have only identified in laboratories in batches of a few atoms at a time. Although the rarity of many of these means that experimental results are not very extensive, their periodic. Whilst francium and radium do show typical properties of their groups, actinides display a much greater variety of behaviour. Prediction Exception to the Madelung rule, francium and radium make up the s-block elements of the 7th period. Francium is an element with symbol Fr and atomic number 87. It was formerly known as eka-caesium and actinium K and it is one of the two least electronegative elements, the other being caesium. Francium is a radioactive metal that decays into astatine, radium. As an alkali metal, it has one valence electron, francium was discovered by Marguerite Perey in France in 1939. It was the last element discovered in nature, rather than by synthesis, outside the laboratory, francium is extremely rare, with trace amounts found in uranium and thorium ores, where the isotope francium-223 continually forms and decays. As little as 20–30 g exists at any time throughout the Earths crust. The largest amount produced in the laboratory was a cluster of more than 300,000 atoms, radium is a chemical element with atomic number 88, represented by the symbol Ra. Radium is an almost pure-white alkaline earth metal, but it readily oxidizes on exposure to air, all isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1601 years and decays into radon gas. Because of such instability, radium is luminescent, glowing a faint blue, radium, in the form of radium chloride, was discovered by Marie Skłodowska-Curie and Pierre Curie in 1898. They extracted the radium compound from uraninite and published the discovery at the French Academy of Sciences five days later, radium was isolated in its metallic state by Marie Curie and André-Louis Debierne through the electrolysis of radium chloride in 1910

32.
Block (periodic table)
–
A block of the periodic table of elements is a set of adjacent groups. The term appears to have been first used by Charles Janet, the respective highest-energy electrons in each element in a block belong to the same atomic orbital type. For discussion of the nature of why the energies of the blocks appear in this order in complex atoms, see atomic orbital. Then, each subshell is repeated as many times as required for each pair of electrons it may contain, the s-block and p-block together are usually considered as the main group elements, the d-block corresponds to the transition metals, and the f-block are the lanthanides and the actinides. Groups in the f-block are not numbered, in addition to the blocks listed in this table, there is a hypothetical g-block which is not pictured here. The g-block elements can be seen in the extended periodic table. The s-block is on the side of the periodic table that includes elements from the first two columns, the alkali metals and alkaline earth metals, plus helium. Most s-block elements are highly reactive due to the ease with which their outer s-orbital electrons interact to form compounds. The first period elements in this block, however, are nonmetals, hydrogen is highly chemically reactive, like the other s-block elements, but helium is a virtually unreactive noble gas. S-block elements are unified by the fact that their valence electrons are in the s orbital, the s-orbital is a single spherical cloud which can contain only one pair of electrons, hence, the s-block consists of only two columns in the periodic table. Elements in column 1, with a single valence electron, are the most reactive of the block. Elements in the column have two s-orbital valence electrons, and, except for helium, are only slightly less reactive. The p-block is on the side of the periodic table and includes elements from the six columns beginning with column 13. Helium, though being in the top of group 18, is not included in the p-block, the p-block is home to the biggest variety of elements and is the only block that contains all three types of elements, metals, nonmetals, and metalloids. Generally, the elements are best described in terms of element type or group. P-block elements are unified by the fact that their valence electrons are in the p orbital, the p orbital consists of six lobed shapes coming off a central point at evenly spaced angles. The p orbital can hold a maximum of six electrons, hence there are six columns in the p-block, elements in column 13, the first column of the p-block, have one p-orbital electron. Elements in column 14, the column of the p-block, have two p-orbital electrons

33.
Atomic orbital
–
In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atoms nucleus. The term, atomic orbital, may refer to the physical region or space where the electron can be calculated to be present. Each such orbital can be occupied by a maximum of two electrons, each with its own quantum number s. The simple names s orbital, p orbital, d orbital and these names, together with the value of n, are used to describe the electron configurations of atoms. They are derived from the description by early spectroscopists of certain series of alkali metal spectroscopic lines as sharp, principal, diffuse, Orbitals for ℓ >3 continue alphabetically, omitting j because some languages do not distinguish between the letters i and j. Atomic orbitals are the building blocks of the atomic orbital model. In this model the electron cloud of an atom may be seen as being built up in an electron configuration that is a product of simpler hydrogen-like atomic orbitals. The lowest possible energy an electron can take is therefore analogous to the frequency of a wave on a string. Higher energy states are similar to harmonics of the fundamental frequency. The electrons are never in a point location, although the probability of interacting with the electron at a single point can be found from the wave function of the electron. Particle-like properties, There is always a number of electrons orbiting the nucleus. Electrons jump between orbitals in a particle-like fashion, for example, if a single photon strikes the electrons, only a single electron changes states in response to the photon. The electrons retain particle-like properties such as, each state has the same electrical charge as the electron particle. Each wave state has a single discrete spin and this can depend upon its superposition. Thus, despite the popular analogy to planets revolving around the Sun, in addition, atomic orbitals do not closely resemble a planets elliptical path in ordinary atoms. A more accurate analogy might be that of a large and often oddly shaped atmosphere, atomic orbitals exactly describe the shape of this atmosphere only when a single electron is present in an atom. This is due to the uncertainty principle, atomic orbitals may be defined more precisely in formal quantum mechanical language

34.
Aufbau principle
–
The Aufbau principle states that, hypothetically, electrons orbiting one or more atoms fill the lowest available energy levels before filling higher levels. In this way, the electrons of an atom, molecule, Aufbau is a German noun that means construction or building-up. The Aufbau principle is called the building-up principle or the Aufbau rule. The details of this tendency are described mathematically by atomic orbital functions. Electron behavior is elaborated by other principles of physics, such as Hunds rule. Hunds rule asserts that if multiple orbitals of the same energy are available, electrons fill unoccupied orbitals first. But, according to the Pauli exclusion principle, in order for electrons to occupy the same orbital, a version of the Aufbau principle known as the nuclear shell model is used to predict the configuration of protons and neutrons in an atomic nucleus. The order in which these orbitals are filled is given by the n + ℓ rule, also known as the Madelung rule, or the Janet rule or the Klechkowsky rule, Orbitals with a lower n + ℓ value are filled before those with higher n + ℓ values. In this context, n represents the quantum number and ℓ the azimuthal quantum number, the values ℓ =0,1,2,3 correspond to the s, p, d. The rule is based on the number of nodes in the atomic orbital, n + ℓ. In the case of equal n + ℓ values, the orbital with an n value is filled first. Copper, chromium, and palladium are common examples of this property, according to the Madelung rule, the 4s orbital is occupied before the 3d orbital. The rule then predicts the configuration of 29Cu to be 1s22s22p63s2 3p64s23d9, however the experimental electronic configuration of the copper atom is 4s13d10. By filling the 3d orbital, copper can be in an energy state. Similarly, chromium takes the configuration of 4s13d5 instead of 4s23d4. In this case, chromium has a half-full 3d shell, for palladium, the Madelung rule predicts 5s24d8, but the experimental configuration 4d10 differs in the placement of two electrons. The principle takes its name from the German, Aufbauprinzip, building-up principle, each added electron is subject to the electric field created by the positive charge of the atomic nucleus and the negative charge of other electrons that are bound to the nucleus. Although in hydrogen there is no difference between orbitals with the same principal quantum number n, this is not true for the outer electrons of other atoms

35.
Properties of metals, metalloids and nonmetals
–
The chemical elements can be broadly divided into metals, metalloids and nonmetals according to their shared physical and chemical properties. All metals have an appearance, are good conductors of heat and electricity, form alloys with other metals. Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconducting forms, typical nonmetals have a dull, coloured or colourless appearance, are brittle when solid, are poor conductors of heat and electricity, and have acidic oxides. Most or some elements in each category share a range of other properties, Metals appear lustrous, form mixtures when combined with other metals, tend to lose or share electrons when they react with other substances, and each forms at least one predominantly basic oxide. Some metals appear coloured, have low densities or very high melting points, are liquids at or near room temperature, are brittle, not easily machined, Metals comprise the large majority of the elements, and can be subdivided into several different categories. Specialized subcategories such as the metals and the noble metals also exist. Most are semiconductors, and moderate thermal conductors, and have structures that are more open than those of most metals, some metalloids conduct electricity like metals. The metalloids, as the smallest major category of elements, are not subdivided further, nonmetals have open structures, tend to gain or share electrons when they react with other substances, and do not form distinctly basic oxides. Some nonmetals are brittle solids at room temperature, the characteristic properties of metals and nonmetals are quite distinct, as shown in the table below. Authors differ in where they divide metals from nonmetals and in whether they recognize an intermediate metalloid category, some authors count metalloids as nonmetals with weakly nonmetallic properties. Others count some of the metalloids as post-transition metals, within each category, elements can be found with one or two properties very different from the expected norm, or that are otherwise notable. Sodium, potassium, rubidium, caesium, barium, platinum, gold The common notions that alkali metal ions always have a +1 charge, the synthesis of a crystalline salt of the sodium anion Na− was reported in 1974. Since then further compounds containing anions of all alkali metals except Li and Fr. In 1943, Sommer reported the preparation of the yellow transparent compound CsAu and this was subsequently shown to consist of caesium cations and auride anions although it was some years before this conclusion was accepted. Several other aurides have since been synthesized, as well as the red transparent compound Cs2Pt which was found to contain Cs+, manganese Well-behaved metals have crystal structures featuring unit cells with up to four atoms. Manganese has a crystal structure with a 58-atom unit cell, effectively four different atomic radii. It has been described as resembling a quaternary intermetallic compound with four Mn atom types bonding as if they were different elements, the half-filled 3d shell of manganese appears to be the cause of the complexity. This confers a large magnetic moment on each atom, below 727 °C, a unit cell of 58 spatially diverse atoms represents the energetically lowest way of achieving a zero net magnetic moment

36.
Metal
–
A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest

Periodic table
–
The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configurations, and recurring chemical properties. This ordering shows periodic trends, such as elements with similar behaviour in the same column and it also shows four rectangular blocks with some approximately similar chemical propertie

1.
Dmitri Mendeleev

2.
Standard form of the periodic table (color legend below)

3.
Glenn T. Seaborg who, in 1945, suggested a new periodic table showing the actinides as belonging to a second f-block series

Alternative periodic tables
–
Alternative periodic tables are tabulations of chemical elements differing significantly in their organization from the traditional depiction of the periodic system. Several have been devised, often purely for reasons, as not all correlations between the chemical elements are effectively captured by the standard periodic table. Alternative periodic

1.
Spiral periodic table (Robert W Harrison)

3.
Mendeleev's Flower (Flower periodic table)

4.
Binary electron shells periodic table

Chemical Galaxy
–
John Drury Clark was the first to present a spiral with an oval outline. His design was used as a vividly coloured two-page illustration in Life magazine for 16 May 1949. In 1951, Edgar Longman, an artist, not a chemist, painted a mural, adapting the Life image by making the shape elliptical. This inspired Stewart, then 12 years old, with a love of

1.
The Chemical Galaxy

2.
The Chemical Galaxy II

3.
Longman Version

History of the periodic table
–
The periodic table is an arrangement of the chemical elements, organized on the basis of their atomic numbers, electron configurations and recurring chemical properties. Elements are presented in order of increasing atomic number, the standard form of the table consists of a grid of elements, with rows called periods and columns called groups. The

1.
Hennig Brand, as shown in The Alchemist Discovering Phosphorus

2.
Antoine Laurent de Lavoisier

3.
Mendeleev's 1871 periodic table. Dashes: unknown elements. Group I-VII: modern group 1–2 and 3–7 with transition metals added; some of these extend into a group VIII. Noble gasses unknown (and unpredicted).

4.
Henry Moseley

Dmitri Mendeleev
–
Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. Mendeleev was born in the village of Verkhnie Aremzyani, near Tobolsk in Siberia, to Ivan Pavlovich Mendeleev and his grandfather was Pavel Maximovich Sokolov, a priest of the Russian Orthodox Church from the Tver region. Ivan, along with his brothers and sisters, obtained new family na

1.
Dmitri Mendeleev in 1897

2.
Signature

3.
Dmitri Mendeleev

4.
Sculpture in honor of Mendeleev and the periodic table, located in Bratislava, Slovakia

Chemical elements in East Asian languages
–
The names for chemical elements in East Asian languages, along with those for some chemical compounds, are among the newest words to enter the local vocabularies. While most East Asian languages use—or have used—the Chinese script, only the Chinese language uses the characters as the predominant way of naming elements, on the other hand, the Japane

1.
A periodic table using simplified Chinese characters

Group (periodic table)
–
In chemistry, a group is a column of elements in the periodic table of the chemical elements. There are 18 numbered groups in the table, but the f-block columns are not numbered. There are three systems of group numbering, the modern numbering group 1 to group 18 is recommended by the International Union of Pure and Applied Chemistry. It replaces t

1.
In the periodic table of the elements, each numbered column is a group.

Alkali metal
–
The alkali metals are a group in the periodic table consisting of the chemical elements lithium, sodium, potassium, rubidium, caesium, and francium. Indeed, the alkali metals provide the best example of trends in properties in the periodic table. The alkali metals are all shiny, soft, highly reactive metals at standard temperature and pressure and

1.
Lithium (Li) 3

2.
Sodium (Na) 11

3.
Potassium (K) 19

4.
Rubidium (Rb) 37

Alkaline earth metal
–
The alkaline earth metals are six chemical elements in column 2 of the Periodic table. They are beryllium, magnesium, calcium, strontium, barium, the elements have very similar properties, they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure. All the discovered alkaline earth metals occur in nature, exper

1.
Beryllium (Be) 4

2.
Magnesium (Mg) 12

3.
Calcium (Ca) 20

4.
Strontium (Sr) 38

Group 3 element
–
Group 3 is a group of elements in the periodic table. This group, like other groups, should contain four elements. When the group is understood to contain all of the lanthanides, three group 3 elements occur naturally, scandium, yttrium, and either lanthanum or lutetium. Lanthanum continues the trend started by two members in general chemical behav

1.
Scandium (Sc) 21 Transition metal

2.
Yttrium (Y) 39 Transition metal

3.
Lutetium (Lu*) 71 Lanthanide

4.
Lawrencium, the only synthetic element in the group, was named after American physicist Ernest Lawrence, the inventor of the cyclotron atom-smasher and founder of discovery place, then-called Lawrence Radiation Laboratory (now Lawrence Berkeley National Laboratory)

Group 4 element
–
Group 4 is a group of elements in the periodic table. It contains the elements titanium, zirconium, hafnium and rutherfordium and this group lies in the d-block of the periodic table. The group itself has not acquired a name, it belongs to the broader grouping of the transition metals. The three Group 4 elements that occur naturally are titanium, z

1.
Titanium (Ti) 22 Transition metal

2.
Zirconium (Zr) 40 Transition metal

3.
Hafnium (Hf) 72 Transition metal

4.
Crystal of the abundant mineral Ilmenite

Group 5 element
–
Group 5 is a group of elements in the periodic table. Group 5 contains vanadium, niobium, tantalum and dubnium and this group lies in the d-block of the periodic table. The group itself has not acquired a name, it belongs to the broader grouping of the transition metals. The lighter three Group 5 elements occur naturally and share similar propertie

1.
Vanadium (V) 23 Transition metal

2.
Niobium (Nb) 41 Transition metal

3.
Tantalum (Ta) 73 Transition metal

Group 6 element
–
Group 6, numbered by IUPAC style, is a group of elements in the periodic table. Its members are chromium, molybdenum, tungsten, and seaborgium and these are all transition metals and chromium, molybdenum and tungsten are refractory metals. The period 8 elements of group 6 are likely to be either unpenthexium or unpentoctium and this may not be poss

1.
Chromium (Cr) 24 Transition metal

2.
Molybdenum (Mo) 42 Transition metal

3.
Tungsten (W) 74 Transition metal

4.
The red colour of rubies is from a small amount of chromium(III).

Group 7 element
–
Group 7, numbered by IUPAC nomenclature, is a group of elements in the periodic table. They are manganese, technetium, rhenium, and bohrium, all known elements of group 7 are transition metals. Like other groups, the members of family show patterns in their electron configurations. Bohrium has not been isolated in pure form, and its properties have

1.
Manganese (Mn) 25 Transition metal

2.
Rhenium (Re) 75 Transition metal

Group 8 element
–
Group 8 is a group of chemical element in the periodic table. It consists of iron, ruthenium, osmium and hassium, like other groups, the members of this family show patterns in electron configuration, especially in the outermost shells, resulting in trends in chemical behavior. Group 8 is the modern IUPAC name for group, the old style name was grou

1.
Iron (Fe) 26 Transition metal

2.
Ruthenium (Ru) 44 Transition metal

3.
Osmium (Os) 76 Transition metal

4.
Iron has been used since antiquity to make tools.

Group 9 element
–
Group 9, numbered by IUPAC nomenclature, is a group of chemical element in the periodic table. Members are cobalt, rhodium, iridium and perhaps also the chemically uncharacterized meitnerium and these are all transition metals in the d-block. All known isotopes of meitnerium are radioactive with short half-lives, and it is not known to occur in nat

1.
Cobalt (Co) 27 Transition metal

2.
Rhodium (Rh) 45 Transition metal

3.
Iridium (Ir) 77 Transition metal

Group 10 element
–
All known isotopes of darmstadtium are radioactive with short half-lives, and are not known to occur in nature, only minute quantities have been synthesized in laboratories. Darmstadtium has not been isolated in pure form, and its properties have not been observed, only nickel, palladium. All three elements are typical silvery-white transition meta

1.
Nickel (Ni) 28 Transition metal

2.
Palladium (Pd) 46 Transition metal

3.
Platinum (Pt) 78 Transition metal

Group 11 element
–
Group 11, by modern IUPAC numbering, is a group of chemical elements in the periodic table, consisting of copper, silver, and gold. Roentgenium is also placed in group in the periodic table. Group 11 is also known as the metals, due to their former usage. They were most likely the first three elements discovered, Copper, silver, and gold all occur

1.
Copper (Cu) 29 Transition metal

2.
Silver (Ag) 47 Transition metal

3.
Gold (Au) 79 Transition metal

Group 12 element
–
Group 12, by modern IUPAC numbering, is a group of chemical elements in the periodic table. It includes zinc, cadmium and mercury, the further inclusion of copernicium in group 12 is supported by recent experiments on individual copernicium atoms. Group 12 is also known as the metals, although this can also more generally refer to any metal that ha

1.
Zinc (Zn) 30 Transition metal

2.
Cadmium (Cd) 48 Transition metal

3.
Mercury (Hg) 80 Transition metal

4.
Sphalerite (ZnS), an important zinc ore

Boron group
–
The boron group are the chemical elements in group 13 of the periodic table, comprising boron, aluminium, gallium, indium, thallium, and perhaps also the chemically uncharacterized nihonium. The elements in the group are characterized by having three electrons in their outer energy levels. These elements have also referred to as icosagens and triel

1.
Boron (B) 5 Metalloid

2.
Aluminium (Al) 13 Post-transition metal

3.
Gallium (Ga) 31 Post-transition metal

4.
Indium (In) 49 Post-transition metal

Carbon group
–
The carbon group is a periodic table group consisting of carbon, silicon, germanium, tin, lead, and flerovium. In modern IUPAC notation, it is called Group 14, in the field of semiconductor physics, it is still universally called Group IV. The group was also known as the tetrels, stemming from the Roman numeral IV in the group names. The group is a

1.
Carbon (C) 6 Polyatomic nonmetal

2.
Silicon (Si) 14 Metalloid

3.
Germanium (Ge) 32 Metalloid

4.
Tin (Sn) 50 Post-transition metal

Pnictogen
–
A pnictogen /ˈnɪktədʒᵻn/ is one of the chemical elements in group 15 of the periodic table. This group is known as the nitrogen family. It consists of the nitrogen, phosphorus, arsenic, antimony, bismuth. In modern IUPAC notation, it is called Group 15, in CAS and the old IUPAC systems it was called Group VA and Group VB respectively. In the field

1.
Nitrogen (N) 7 Diatomic nonmetal

2.
Phosphorus (P) 15 Polyatomic nonmetal

3.
Arsenic (As) 33 Metalloid

4.
Antimony (Sb) 51 Metalloid

Chalcogen
–
The chalcogens are the chemical elements in group 16 of the periodic table. This group is known as the oxygen family. It consists of the oxygen, sulfur, selenium, tellurium. The chemically uncharacterized synthetic element livermorium is predicted to be a chalcogen as well, the word chalcogen is derived from a combination of the Greek word khalkόs

1.
Sulfur (S) 16 Polyatomic nonmetal

2.
Selenium (Se) 34 Polyatomic nonmetal

3.
Tellurium (Te) 52 Metalloid

4.
The four stable chalcogens at STP

Halogen
–
The halogens or halogen elements are a group in the periodic table consisting of five chemically related elements, fluorine, chlorine, bromine, iodine, and astatine. The artificially created element 117 may also be a halogen, in the modern IUPAC nomenclature, this group is known as group 17. The symbol X is often used generically to refer to any ha

1.
Fluorine (F) 9 Halogen

2.
Chlorine (Cl) 17 Halogen

3.
Bromine (Br) 35 Halogen

4.
Iodine (I) 53 Halogen

Noble gas
–
The noble gases make a group of chemical elements with similar properties, under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are helium, neon, argon, krypton, xenon, oganesson is predicted to be a noble gas as well, but its chemistry has not yet b

1.
Helium (He) 2

2.
Neon (Ne) 10

3.
Argon (Ar) 18

4.
Krypton (Kr) 36

Period (periodic table)
–
A period in the periodic table is one of the horizontal rows, all of whose elements have the same number of electron shells. Going across a period, each element has one proton and is less metallic than its predecessor. Arranged this way, groups of elements in the column have similar chemical and physical properties. For example, the alkaline metals

2.
In the periodic table of the elements, each numbered row is a period.

Period 1 element
–
A period 1 element is one of the chemical elements in the first row of the periodic table of the chemical elements. The first period contains fewer elements than any other row in the table and this situation can be explained by modern theories of atomic structure. In a quantum description of atomic structure, this period corresponds to the filling

1.
Hydrogen discharge tube

2.
Helium discharge tube

3.
Deuterium discharge tube

Period 2 element
–
A period 2 element is one of the chemical elements in the second row of the periodic table of the chemical elements. The second period contains the elements lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine and this situation can be explained by modern theories of atomic structure. In a quantum description of atomic structure, this peri

1.
Lithium metal floating on paraffin oil

3.
Large piece of beryllium

4.
Boron chunks

Period 3 element
–
A period 3 element is one of the chemical elements in the third row of the periodic table of the chemical elements. The third period contains eight elements, sodium, magnesium, aluminium, silicon, phosphorus, sulfur, chlorine, the first two, sodium and magnesium, are members of the s-block of the periodic table, while the others are members of the

Period 4 element
–
A period 4 element is one of the chemical elements in the fourth row of the periodic table of the elements. The fourth period contains 18 elements, beginning with potassium and ending with krypton, as a rule, period 4 elements fill their 4s shells first, then their 3d and 4p shells, in that order, however, there are exceptions, such as chromium. Ev

1.
Period 4 in the periodic table

2.
Potassium

Period 7 element
–
A period 7 element is one of the chemical elements in the seventh row of the periodic table of the chemical elements. The seventh period contains 32 elements, tied for the most with period 6, beginning with francium and ending with oganesson, the heaviest element currently discovered. As a rule, period 7 elements fill their 7s shells first, then th

1.
The atomic bomb dropped on Nagasaki had a plutonium charge.

Block (periodic table)
–
A block of the periodic table of elements is a set of adjacent groups. The term appears to have been first used by Charles Janet, the respective highest-energy electrons in each element in a block belong to the same atomic orbital type. For discussion of the nature of why the energies of the blocks appear in this order in complex atoms, see atomic

1.
s-block

Atomic orbital
–
In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom. This function can be used to calculate the probability of finding any electron of an atom in any specific region around the atoms nucleus. The term, atomic orbital, may refer to the physi

1.
The shapes of the first five atomic orbitals: 1s, 2s, 2p x, 2p y, and 2p z. The two colors show the phase or sign of the wave function in each region. These are graphs of ψ(x, y, z) functions which depend on the coordinates of one electron. To see the elongated shape of ψ(x, y, z) 2 functions that show probability density more directly, see the graphs of d-orbitals below.

2.
False-color density images of some hydrogen-like atomic orbitals (f orbitals and higher are not shown)

Aufbau principle
–
The Aufbau principle states that, hypothetically, electrons orbiting one or more atoms fill the lowest available energy levels before filling higher levels. In this way, the electrons of an atom, molecule, Aufbau is a German noun that means construction or building-up. The Aufbau principle is called the building-up principle or the Aufbau rule. The

1.
Order in which orbitals are arranged by increasing energy according to the Madelung rule. Each diagonal red arrow corresponds to a different value of n + ℓ.

Properties of metals, metalloids and nonmetals
–
The chemical elements can be broadly divided into metals, metalloids and nonmetals according to their shared physical and chemical properties. All metals have an appearance, are good conductors of heat and electricity, form alloys with other metals. Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconduc

2.
Tellurium, described by Dmitri Mendeleev as forming a transition between metals and nonmetals

3.
25 ml of bromine, a dark red-brown liquid at room temperature

Metal
–
A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are non

3.
Glenn T. Seaborg and his group at the University of California at Berkeley synthesized Pu, Am, Cm, Bk, Cf, Es, Fm, Md, No and element 106, which was later named seaborgium in his honor while he was still living. They also synthesized more than 100 atomic actinide isotopes.

1.
The atomic number of hydrogen is 1. The standard atomic weight of hydrogen is 1.008 (this value is not given here as an expectation interval, as it is in elements below). Atomic weight is the same as relative atomic mass. The atomic weights of samples of hydrogen will vary according to their content of heavy hydrogen (deuterium), and this will in turn depend upon where the samples are collected.

2.
Julius Caesar 's Commentarii de Bello Gallico is one of the most famous classical Latin texts of the Golden Age of Latin. The unvarnished, journalistic style of this patrician general has long been taught as a model of the urbane Latin officially spoken and written in the floruit of the Roman republic.